Yao Choy

Yu choy by another name

“Yao choy” is one of several vernacular names for the same vegetable across different Cantonese-speaking regions:

• Yao choy — Cantonese pronunciation (used in Hong Kong, Guangdong)
• Yu choy — Mandarin pronunciation
• Choy sum — Cantonese name for “heart of the vegetable” (referring to the flowering stem)

All three terms refer to Brassica rapa var. parachinensis — a leafy stem vegetable that’s a cousin of bok choy but with a distinctly different growth habit.

Eat the flowers (almost)

Unlike most leafy vegetables, yao choy is harvested when starting to flower — young plants with small bright yellow flower buds and slightly elongated stems are the prime quality.

This is why one of the Cantonese names is “choy sum” (菜心) — meaning “heart of the vegetable” — referring to the flowering stem at the heart of the plant. Older yao choy with fully opened flowers becomes bitter and tough; younger plants without any flower buds aren’t quite at peak flavor.

Cantonese cooking essential

In Cantonese cuisine, yao choy is a fundamental green — appearing in almost every Cantonese restaurant and home kitchen. Common preparations:

• Yu choy with oyster sauce — blanched stems and leaves, drizzled with oyster sauce, garlic oil, and sesame oil
• Stir-fried with garlic — quick high-heat preparation, bright green when done right
• Boiled in soup or hot pot — adds vegetal freshness and color
• Side to dim sum — small portions of blanched yu choy alongside dumplings

The vegetable’s mild sweetness and tender texture make it accessible even to people unfamiliar with Asian greens.

Sweet-mustard flavor profile

Yao choy has a distinctive flavor that’s mild but distinctive:

• Subtly sweet (less than spinach but more than lettuce)
• Slightly mustard-y (less than rapini but in the same family)
• Slightly cabbage-like (less than bok choy)
• Fresh and grassy

The flavor changes with cooking — raw young leaves are mild and slightly peppery; blanched is sweeter and more vegetal; stir-fried develops a slight bitterness that complements bold seasonings.

Quick to grow

Yao choy is one of the fastest-growing leafy vegetables — typically just 35-45 days from seed to harvest for baby leaves, or 50-60 days for full plants with flowering stems. This rapid growth makes it ideal for:

• Succession plantings throughout the cool season
• Hot-climate growers needing quick-turn crops
• Home gardeners seeking continuous harvests
• Hydroponic farms

The fast growth also means yao choy is inexpensive at Asian markets — typically much less expensive per pound than slower-growing imported greens.

Confusable with similar vegetables

Asian groceries often stock several similar-looking greens that are genuinely distinct:

• Yao choy / Yu choy / Choy sum (this entry) — flowering stem vegetable, smaller bok choy
• Bok choy — bigger, with thick white stems and large leaves
• Gai lan / Chinese broccoli — thicker stems, larger leaves, more bitter
• Tatsoi — flat rosette of small dark green leaves
• Chinese mustard greens — more pungent and bitter

For shoppers learning Asian vegetables, the best approach is to ask the grocer specifically for the name in Chinese characters or pinyin, since English labeling varies.

Late spring and fall windows

Yao choy bolts (flowers prematurely) in summer heat, making late spring and fall the ideal growing seasons in temperate climates. In subtropical regions like Hong Kong and southern China, yao choy can be grown nearly year-round, with summer slowdowns.

Imported yao choy at North American Asian groceries typically comes from California greenhouse operations year-round, but local-farm yao choy is most abundant in spring and fall.